Linear fast shutdown technology based on self-resonant constant voltage clamping  

基于自谐振恒压钳位的线性快速关断技术

作　　者：SUN De-li SONG Shuang TENG Fei 孙德立;宋爽;滕飞(吉林大学仪器科学与电气工程学院,吉林长春130061)

机构地区：[1]College of Instrumentation&Electrical Engineering,Jilin University,Jilin 130061,China

出　　处：《Journal of Measurement Science and Instrumentation》2020年第3期297-306,共10页测试科学与仪器（英文版）

摘　　要：Transient electromagnetic method(TEM)has been widely used in the field of medium and shallow underground detection due to its high detection efficiency and large detection depth.However,due to the long turn-off time of the transmitting current caused by the inductive characteristics of the transmitting coil,the early signals will be overwhelmed by primary field.Since the early signals contain most of shallow geological signals,it is necessary to reduce the long turn-off time to get shallow layer signal.Due to lack of a reliable and effective clamping method for high-power transmission at present,we design a TEM transmitter fast turn-off circuit,combining self-resonant zero-voltage switching technology with the corresponding timing control circuit to solve this problem effectively.A transient electromagnetic transmitter based on self-resonant constant voltage clamping technology was fabricated to charge the clamping capacitor.The rated transmitting current of the transmitter is 20 A,and the turn-off time is continuously adjustable from 550-50μs.Moreover,the current drop process is approximately linear rather than exponential attenuation.Compared with the existing clamping methods,the proposed clamping method solves the problems that transient voltage suppressor(TVS)clamping cannot be used in high-power occasions and has a high failure rate.It also solves the problem of long pre-charge time in traditional capacitor clamping methods due to insufficient inductance of the small size transmitting coil.The proposed method can provide a reference for fast shutdown of large current.

关 键 词：transient electromagnetic method(TEM) constant voltage clamp zero voltage switch(ZVS) linear turn-off 

分 类 号：O441[理学—电磁学]